I dunno if Hatori Hanzo is particularly swayed by vast amounts of money. I mean...the guy has enough swords in his attic to make him rich enough to own his own country....
yet all he owns is a sushi restaurant? I'm sure those swords were created as some sort of gift or something. I wish they would have made that part of the movie a little clearer.
Why did Hanzo make the sword for Beatrix? He said she owed him it...but why? what was said or what deal was made?
Guess: Hanzo made Bill a sword. Bill became a murdering bastard, Hanzo didnt agree. So he sympethises with the Bride's aim to kill him, also because Bill was a student of Hanzo's and he's using Hanzo's training to murder other people.
As he's Hanzo's ex-student, he ows the Bride at least the chance to get even. So he gives her a sword.
Just speculating.
EDIT: And yeah, it was probably a gift to Bill, as he was one of his students.
But still its worth a million, and selling it for 250 hurts (to both actually).